“We see this as a product for real mass decarbonisation”

Kensa’s Dr Matt Trewhella speaks to Siobhan O’Neill about the company’s latest launch – a widescale alternative to the gas grid.

This week Kensa launches what it describes as a “game-changing” heat pump which it hopes will drive uptake in UK homes, working towards the decarbonisation of heating for around 60% of properties.

Former CEO Dr Matt Trewhella, Director of Strategic Business Development, Kensa Group, took time out from the launch to explain the ambitious vision for a widescale alternative to the gas grid, to support Britain’s 2050 net zero targets.

Describing the Shoebox NX ground source heat pump and Kensa’s plans, Trewhalla tells us: “It’s been very much designed with what we see as the future of heating in mind. We came up with this vision three or four years ago, where you replace the gas grid which is delivering a low-grade chemical energy to a white box in your house. When you want to be warm, you whack your thermostat up, the white box fires up, the radiators get warm, your house gets warm. You pay for the energy and the standing charge for access to the infrastructure that’s delivering that. Our vision is to have a low carbon version of exactly the same thing.”

Kensa is partnering with investors Octopus Energy and Legal & General, and has created Kensa Utilities to support the development of an infrastructure that will enable the mass adoption of networked heat pumps across the country.

The Shoebox NX’s compact size and low noise level are two aspects that makes the heat pump more accessible for homeowners. With the power and efficiency of larger pumps, Kensa’s new model can be housed with a water tank in a similar space to a combi boiler, making it practical for flats and terraced houses.

Tackling misinformation

Addressing retrofit issues and criticisms that have been levelled at heat pump technology being incompatible with older radiators, Trewhella describes the claims as ‘misinformation’. Modern radiators that are designed to run with boilers operating at around 50 degrees would have no issues switching to a heat pump, he said. But he agrees that systems dating to 25 years old might need modernising.

With its announcement this week, Kensa is hoping that architects and the construction industry will see the possibilities their approach offers. “It’s quickest and easiest to start off in new builds,” Trewhella agrees. “But actually we see this as a product for real mass decarbonisation when you come to take a whole city or a whole postcode at a time.”

Kensa Utilities aim to work with localities to put a privately funded infrastructure in place ahead of neighbourhoods adopting heat pumps: much like cabling companies adding the means for homes to switch to cable before any customers have signed on the dotted line. This lowers the upfront installation costs, with consumers paying a standing charge as part of their energy bill to connect to a shared ambient heat network, giving them access to low-cost, low-carbon heat.

“High rise buildings and terraced streets, those sort of buildings which make up around half of the UK, maybe 60%, we think have been excluded from the possibility of low carbon heating,” says Trewhella, “So networked heat pumps with the sharing of the ground arrays – the same way as you share the gas network – solves that issue.”

Despite the possibilities their launch opens up, Trewhella doesn’t expect to see more widespread adoption in existing homes until the 2030s. “Everyone’s still allowed to burn gas, it’s not even being taxed, it’s still being subsidised, so at the moment, there’s no huge financial imperative for people living in a gas-heated home to get a heat pump,” he admits.

But this does give them time to work on the infrastructure network which Trewhella says would be “paid for, owned, managed and maintained” by Kensa Utilities. This would see pipes run through the street and three homes sharing one bore hole to access the ground source heat.

Trewhella describes how he sees it working. “We’ve started bringing down costs by drilling fewer bore holes, drilling them deeper, and sharing them amongst properties,” he said. “In a normal terraced street you might need a 60 metre deep bore hole. It’s actually far cheaper to drill one bore hole that’s 200 metres deep and share it between three homes. So if you picture that street with a network of bore holes all linked together. They’re only about 5 inches across, so the street itself has loads of space available. Once you use the public space, that moves us away from trying to get into a tiny front garden that terraced houses have. So you can imagine that every other car in the street would have a bore hole under it.”

Trewhella is clearly excited about the future the Shoebox NX could open up for the UK and is keen to allay some of the common criticisms he hears about heat pumps burning gas to run the pump. “We did quite a detailed calculation that if you took all of the houses that are currently heated by gas and converted them to a heat pump tomorrow – on a networked heat pump like the NX – and then had no renewables on the grid and only made electricity by burning gas, it would still burn less than half of it,” he says. “The heat pumps are so efficient that even with a really inefficient power station, you’ll still burn a lot less gas. So we could offset all of the gas that we’re currently importing,” he smiles.

Networked ground source heat pump stats:

  • Networked ground source heat pumps are up to 20% cheaper to run than air-source heat pumps, whilst upfront costs are 8% less when installed at scale as part of a funded heat network:
    • For a typical 3-bed Victorian terraced house, a networked ground source heat pump can cost £900 (8%) less than an air-source heat pump to install due to its smaller size and the lack of external installation work required.
    • Due to their higher efficiency, lower maintenance and longer life expectancy, the annual costs of running a networked ground source heat pump are up to 20% lower than an air-source heat pump.
  • Networked ground source heat pumps consume 40% less electricity to provide the same heat as air source equivalents, reducing peak strain on the grid.

Shoebox NX heat pump performance facts and figures:

  • Small and compact, but packs the power and efficiency of large heat pumps – making the most efficient and lowest carbon form of heating accessible to properties with limited space.
  • High efficiency, low electricity usage and low maintenance deliver long-term cost savings for consumers compared to air source heat pumps, and even gas boilers.
  • Is five times more efficient than a gas boiler – Coefficient of Performance of 4.36 (gas boilers typically operate at 0.9).
  • Has an A+++ energy efficiency rating and a 25-year life expectancy.
  • Can heat water to over 60oC without the need for an immersion heater.
  • Can provide passive cooling to cool homes during the summer at a much lower cost than air-conditioning.
  • Designed to work in flats, apartments, terraced houses, tenements and new build properties.

Kensa is exhibiting at InstallerSHOW 2024, running 25-27 June at the NEC. Get your free ticket: installer-2024-splash.reg.buzz